You could use the KDE User Manager (KUser, on the System menu) and avoid all this mess, although you'd have to set a root password first.

But to avoid the RPC error, start the portmap daemon first, as root: /etc/init.d/portmap start

Then, you'll get errors about Knoppix not being able to open the shadow group file, which you can duck by making your user a member of an existing group.

For example, as root: adduser --ingroup knoppix eco2geek

HTH.